1 /**
2 * Copyright (c) 2011, The University of Southampton and the individual contributors.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without modification,
6 * are permitted provided that the following conditions are met:
7 *
8 * * Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 *
11 * * Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * * Neither the name of the University of Southampton nor the names of its
16 * contributors may be used to endorse or promote products derived from this
17 * software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
23 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
26 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30 package org.openimaj.image.processing.threshold;
31
32 import org.openimaj.image.FImage;
33 import org.openimaj.image.processing.algorithm.FilterSupport;
34 import org.openimaj.image.processing.algorithm.MinMaxAnalyser;
35
36 /**
37 * Adaptive local thresholding using the local contrast. Pixels are set to 1 if
38 * they are closer to the local maximum rather than the local minimum.
39 *
40 * @see <a
41 * href="http://fiji.sc/wiki/index.php/Auto_Local_Threshold">http://fiji.sc/wiki/index.php/Auto_Local_Threshold</a>
42 *
43 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
44 *
45 */
46 public class AdaptiveLocalThresholdContrast extends AbstractLocalThreshold {
47 /**
48 * Construct the thresholding operator with the given patch size (assumed
49 * square)
50 *
51 * @param size
52 * size of the local image patch
53 */
54 public AdaptiveLocalThresholdContrast(int size) {
55 super(size);
56 }
57
58 /**
59 * Construct the thresholding operator with the given patch size
60 *
61 * @param size_x
62 * width of patch
63 * @param size_y
64 * height of patch
65 */
66 public AdaptiveLocalThresholdContrast(int size_x, int size_y) {
67 super(size_x, size_y);
68 }
69
70 @Override
71 public void processImage(FImage image) {
72 final MinMaxAnalyser minimax = new MinMaxAnalyser(FilterSupport.createBlockSupport(sizeX, sizeY));
73 minimax.analyseImage(image);
74
75 final float[][] minpix = minimax.min.pixels;
76 final float[][] maxpix = minimax.max.pixels;
77 final float[][] ipix = image.pixels;
78
79 for (int y = 0; y < image.height; y++)
80 for (int x = 0; x < image.width; x++)
81 ipix[y][x] = (ipix[y][x] - minpix[y][x]) > (maxpix[y][x] - ipix[y][x]) ? 1 : 0;
82 }
83 }